The present invention relates to a new strain Lactobacillus sp. KPB-167 (the Accession Number given to this by the International Depositary Authority is FERM BP-2303) that belongs to the genus Lactobacillus and is isolated from kefir grains. The present invention also relates to a method of manufacturing viscose polysachharides in which this new strain is cultured on a predetermined medium.
Kefir grains are known as the starter of kefir, a type of fermented milk traditionally known in the Caucasus, U.S.S.R. Kefir grains are lumps of microorganisms such as lactic acid bacteria and yeasts in symbiosis wherein the support medium is provided by polysaccharides produced by capsule forming bacteria. Since polysaccharides produced by capsule forming bacteria are capable of exhibiting such favorable actions as the promotion of digestive functions, and antitumor actions, they are used as medicines. They are also used in a wide variety of applications such as food additives employed to cause thickening or gelation of a food, and functional macromolecular materials.
Capsule forming bacteria were previously isolated from kefir grains by Rossi et. al. (1978), Ohara (1980), Ohta et. al. (1984), and Adachi et. al. (1986). However, all of the previously isolated strains have strong selectivity for specific media. For instance, according to the method disclosed in Japanese Patent Laid-Open No. 257197/1986 which employs the strain Lactobacillus WT-1 previously isolated by Adachi et. al., a medium containing wine as the essential component must be used, and it is impossible to manufacture polysaccharides otherwise. Furthermore, the conventionally isolated strains have involved the drawback that the productivity of polysaccharides drops during subculture (or preservation).